In your opinion, which US university offers the best Master's and Ph.D. program in fluid mechanics?

The best for what?

- Experimental? - CFD? - Theoretical? - Aerodynamics? - Aeroacoustics? - Flow control? - Biofluids? - Non-newtownian fluids? - I could go on....

Your question is far too broad. If you're considering a graduate degree you must have some idea of what you want to pursue.

I am interested in CFD.

Okay, now within that, again, what are you interested in?

- combustion modeling? - turbulence/transition modeling? - aeroelasticity? - biofluids? - aerodynamics? - LES? - design optimization? - etc....

This will help narrow your search.

hmm, i belive that it is not depend on the desired branch, what is important is that it make you a cfdman that could works in any branch in future,

then you should be careful about graduate program, considering this i belive that University of Texas at Austin (http://www.ices.utexas.edu/ices/) is pretty good their members are relatively good on both of theoric and application sides of cfd.

of course there are other place, maybe better, i do not know !